In manufacturing a semiconductor device, the substrate may be separated from the semiconductor layer after crystal growth of a semiconductor layer on a substrate. For instance, in manufacturing an LED (light emitting diode) based on gallium nitride (GaN), a substrate made of e.g. sapphire or silicon is used as a growth substrate, and separated from the GaN layer. Specifically, for instance, the grown semiconductor layer is bonded to a support substrate, and then the growth substrate is separated from the semiconductor layer. At this time, low melting point solder, for instance, is sandwiched at the bonding surface between the semiconductor layer and the support substrate. These are entirely heated under pressure applied thereto in order to bond the semiconductor layer and the support substrate. This heating may damage the semiconductor layer.